Batteries are a critical part of our everyday lives. From phones to laptops to cars to grid energy storage—batteries are essential to many devices. Lithium ion batteries have taken the lead in battery technology, with lithium iron phosphate batteries (LFP) performing particularly well. While it was known that LFP batteries could charge quickly and withstand many factors, the reasons for this were unknown until know.

A team of researchers from the Paul Scherrer Institute and Toyota Central R&D Labs has discovered why LFP batteries can be recharged so rapidly. The team is comprised of ECS member Tsuyoshi Sasaki, past members Michael Hess and Petr Novak, and Journal of The Electrochemical Society (JES) published author Claire Villevieille.

The reason: the step-like concentration gradient gives way to a gentle, ramp-like progression of the lithium concentration. This is because, at higher voltages, the lithium ions involved in the charging process are distributed across the volume of the electrode particles for brief moments as opposed to being herded together in a thin layer boundary. As a result, the lithium can be set in motion more easily during charging, without the need for more energy to be added to negotiate the layer boundary.